I'm the creator of Ghostty. This isn't right. It should idle at 0 to 1%, as supported by sibling comments. If you can collect more details about your system please open a discussion on the main Ghostty repo. Same with memory.

In terms of speed, same thing: if you can provide some kind of objectively measurable thing, we can look into it. Everything we've measured so far firmly places Ghostty in the "fast" camp (with friends such as Kitty).

We're sometimes faster, sometimes slower, but in any case not noticeably so. You wouldn't pick Ghostty vs Kitty for example for performance, it'd be something else. But you would pick Ghostty over say... iTerm2 for performance (but you may pick iTerm2 for features, its extremely feature rich!).